Nikon’s Small World competition honors images of objects too small for the unaided eye to see. Wim van Egmond, a photographer from The Netherlands, won first place in the 2013 contest for his image of Chaetoceros debilis, a colonial diatom, a type of algae.

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Photo: Joseph Corbo/Nikon Small World

This year's second prize went to Joseph Corbo,for his photo of a painted turtle's retina, the light-sensitive membrane inside the eye.

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Photo: Alvaro Esteves Migotto/Nikon Small World

Alvaro Migotto, a researcher at the University of São Paulo, took home third prize for his magnified image of a marine worm.

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Photo: Rogelio Moreno Gill/Nikon Small World

Rogelio Moreno Gill created this photo of a Paramecium, showing the nucleus, mouth and water expulsion vacuoles.